In late 1931 Chancellor Bruening proposed a radical plan to prevent the Nazis from achieving power and Hitler becoming President of the Republic: his plan was to restore the Hohenzollern throne.
At the time it was believed that Hindenburg would not run again for the presidency in 1933. Without Hindenburg in the race, Hitler would almost certainly be elected president. Even if Hindenburg could be persuaded to run and he won, his great age meant that it would be very unlikely that he would serve out his full term as president; consequently another presidential election would be likely in only a few years, Hitler would only have to be patient for a short while.
Bruening plan to prevent this was to cancel the 1933 presidential elections and extend Hindenburg’s term in office indefinitely. To do so was rather surprisingly, entirely constitutional; all it required as a two thirds vote in both the Reichstag and the Reichsrat, and this Bruening had already managed to negotiate. He had the support of the Social Democrats (reluctantly, but anything to stop Hitler), the centre parties and was confident of enough loyalty to Hindenburg from the right to swing it. Once election was cancelled, Bruening would propose that the parliament proclaim a monarchy with Hindenburg named as regent, to be succeeded by one of Crown Prince Wilhelm’s sons when he died.
Bruening was confident that a constitutional monarchy modelled on the British example would spell the end to the Nazi Party’s political momentum. All he now needed was the agreement of Hindenburg and the Weimer Republic would pass into the pages of history; not to be replaced by National Socialist Revolution, but by Hohenzollern Restoration.
And here’s where Bruening’s plan came unstuck. It wasn’t that Hindenburg was opposed to a restoration; it was that he wanted the restoration to be literally that; Hindenburg would only accept the exiled Wilhelm II returning to the throne. Worse, he wanted it to be a full restoration; a resumption of the absolute monarchy of 1914. The aging Field Marshal was already beginning to slip into senility and when Bruening explained that the Social Democrats had only very reluctantly accepted the return of the monarchy on condition that it was a constitutional monarchy, and that it must not be either Wilhelm II or his son, he was incensed and ended the discussion and there the whole plan died.
So perhaps with just a little more planning Bruening can win over Hindenburg? He’d already managed to persuade the staunchly republican Social Democrats that a Hohenzollern, while not perfect was far better than a Hitler, so finding a means of convincing the Field Marshal is hardly a long stretch. What he needed to do was persuade Hindenburg that this plan was the only way to stop ‘that Austrian Corporal’ from ever sitting in the president’s chair and that honour didn’t demand the return of the exiled Kaiser, just one of his line. Taking the old Kaiser into his confidence probably would have been enough; a letter from Wilhelm II to Hindenburg supporting Bruening’s plan for the sake of Germany’s future, while at the same time renouncing any claim to the throne for himself in favour of his grandson, would probably have been enough to do it. If Wilhelm were aware that this was the only way for the Hohenzollerns to ever return to the throne of Germany, he would have jumped at the chance. If Bruening had presented his plan to Hindenburg with all the pieces already in place, including the vital endorsement of the old Kaiser, the old man would have grudgingly accepted it.
1933 would have seen the end of the German Republic, the declaration of the Regency, and the return to Germany of Prince Louis Ferdinand* from America. A supporter of constitutional monarchy and staunch opponent of the Nazis, Louis could be expected to win over the Social Democrats, and consequently the support of all but the Nazis and the Communists.
The question then is, would this really derail the Nazi juggernaut or would the Regency give them sufficient time to seize power?
*Sorry, Louis not Wilhelm. Wilhelm, like Edward VIII would shortly do, chose love over duty.